This invention relates to an apparatus for cutting an extruded product and more particularly to an apparatus for using the cutting action to force a cut extruded product in an upward direction to provide cooling and dissipation of heat through a vapor-permeable shroud surrounding the cutting edge and permit the product to be recovered without substantial deformation thereof.
A standard means known in the art for shaping a product is by use of an extruder. Basically, the extruder forces a mass of product through a die, and the product thus shaped by the die is recovered. In some cases, it is desired to recover small particles of an extruded material. This recovery of small particles is usually accomplished by providing a cutting device to cooperate with the die and force the cut extruded product down onto a conveyor belt. Due to the presence of the cutting device, a shroud is necessary to protect the operator of such a device from the cutting device. For many reasons this standard cutting operation is not suitable in a variety of extruding processes. For example, this cutting process is not suitable for extrusion of certain types of food exemplified by, but not limited to cereals, snacks, and pet foods.
One reason that the standard cutting device is not suitable for many products--especially some food products--is that the standard safety device surrounding a cutting device is a solid shroud. The shroud is relatively small and designed primarily to cover the cutting edges of the cutting system to prevent access thereto while the cutting device is in operation. This shroud also traps heat if the extruded product has been heated. Yet a heated extruded product is standard in the food processing art for process ability and cooking purposes. This entrapment of heat causes steam and condensate build-up inside the shroud. Furthermore, the small size of the shroud leads to contact of the extruded food products with the shroud to such an extent that the food product is deprived of the desirable form for the product.
In order to avoid contact with the shroud, a cutting system is customarily arranged to throw the cut product in a downward direction so that the product contacts a suitable removing device such as a conveyor belt. This conveyor belt concept also causes problems in the food processing area. The particles of food contact the conveyor belt at relatively high velocity resulting in deforming of the product. The high velocity results from both gravitational force and the downward momentum imparted to the food particle by the downward stroke of the cutter which is added to the gravitational force. These forces plus the short time between cutting and belt contact can result in product deformation--especially because the product is still warm from the extruder and has insufficient time to dry. Also, clumping of the product may occur if the belt is not moved fast enough to avoid the contact between the various pieces of the product, because the product is coming down so fast that intra piece contact is almost inevitable. Yet, this contact is sometimes unavoidable because of the small shroud and the desirability of focusing the product on a certain area in order to provide the necessary protection for the operator from the cutting device. This fast running of the conveyor belt to avoid the clumping is not always effective and does not minimize the contact with the belt which can also cause product deformation. Accordingly, the solution to the protection of the cutting system and removal of the product from the extruder creates a substantial number of problems which interfers with an efficient system of recovering the products.
Various corrections are possible to solve the above-referenced problems. It is possible to use a cooler extrusion temperature. However, this cooler extrusion temperature has an effect on a food product in that the product cannot be as thoroughly cooked within the extruder and can change product characteristics. It is also possible to reduce the moisture content of the extruded product to avoid the steam build-up when the product exits from the extruder. This moisture reduction, however, inhibits the proper flow of the extrudate within the extruder and adversely affects the appearance and texture of the food. Accordingly, the recovery of the product from the extruder presents a substantial number of problems which interfere with efficient extruder production. When one product problem is corrected, another problem is created which compounds the extrusion problem. Accordingly, it is desired to provide a cutting system and process which permits the recovery of the product from an extruder while avoiding the problems of the prior art.